Resistive heating is a method of heating a workpiece by flowing electrical current through a resistive heating element. The temperature of the resistive heating element rises due to the flow of electric current through the resistive heating element. Heat is transferred from the resistive heating element to the workpiece by a method of heat transfer, such as thermal conduction. By contrast, induction heating is a method of heating a workpiece by using a magnetic field to induce electric currents in the workpiece. The electric currents in the workpiece cause the temperature of the workpiece to rise.
Induction heating involves applying an AC electric signal to a heating loop or coil placed near a specific location on or around an object, such as a metal, to be heated. The varying or alternating current in the loop creates a varying magnetic flux. Electrical currents are induced in the object by the magnetic flux. The object is heated by the flow of electricity induced in the object by the alternating magnetic field. Induction heating may be used for many different purposes, such as pre-heating a metal before welding, post-heating a weld joint, stress relieving a weld joint, annealing, surface hardening, etc.
Electrical conductors within an induction heating cable may serve as the loop or coil to produce the magnetic field. A source of electrical power is coupled to the induction heating cable to produce the magnetic field. However, in contrast to a resistive heating element, it is not desirable to heat the induction heating cable with the flow of electricity through the induction heating cable. Additionally, the high temperatures that a workpiece may experience during induction heating could damage or destroy an induction heating cable. Consequently, fluid-cooled induction heating cables have been developed to remove heat from the induction heating cable. Cooling units are used to pump cooling fluid through the induction heating cable to remove heat.
Current induction heating cables utilize a single integral connector located at each end of the induction heating cable to both fluidicly and electrically couple the induction heating cable to a coolant source and a current source. Additionally, the single connector is threaded to a corresponding connector to complete the electrical and fluidic coupling. However, the single integral connector design is complicated and difficult to manufacture. Additionally, securing each connector to an opposing connector is time consuming and requires tools to complete.
There is a need therefore for a fluid-cooled induction heating cable that avoids the problems associated with an integral electric and fluidic connector. Specifically, there is a need for a fluid-cooled induction heating cable that physically separates the portions of the induction heating cable that are used to electrically couple the induction heating cable to a source of electrical current from those portions of the induction heating cable that are used to fluidicly couple the induction heating cable to a source of cooling fluid. Additionally, there is a need for a connector assembly for a fluid-cooled induction heating cable that is easy to assemble and which can be quickly connected and disconnected without the use of tools.